the REAL facts about fuel "economy" on the CTD trucks!!

[AGrubbs]

MPG's small truck..

I can relate to that. . I had a '94 S-10 4x4 with 4. 3l automatic. I sold it to my dad when I got my '03 CTD.



The BEST I got from the s-10 was 21 MPG HiWay, and usually only 17-19 MPG.

In summer with my '03 4x4 6 speed Qcab I get 22-24 MPG hand calc. on mostly hiway (60 MPH) with maybe only 50-100 miles in the city on most every tank. Speed up to 75 and it drops to about 18 - 19 MPG though...



Only major mods to the '03 are a box topper and Smarty on level 1 or 3, and running boards!

 

[jnelson]

Hand figured 2 weeks ago. Towing an empty 16 ft. tongue pull trailer back from Coffeyville KS. Chip on level 1.



18. 06 mpg.



I ususally dont figure my mpg for the fact that I seldom run a tank without putting something in the bed or hooking up to a trailer.

 

[imaybail]

I believe the biggest difference lies in the final drive ratio of our trucks. When compared with the big rigs, our final drive, which in the auto is close to 1:1 is much less efficient than the final drive in a road tractor with 18 speed transmission and possibly a dual ratio diff.

Anybody know what the typical final drive ratio is on a road tractor?



Great discussion here and a wealth of knowledge to consider and capitalize on.



ben

 

[Mallgeyer]

18 speeds

a 18 speed eaton fuller's top gear . 73 next gear down is a . 86. 1st gear is a 14. 40. most of your semis today run a 10 speed . 74 10th gear. most guys are running a 3. 54 to 3. 90 rearend ratio. nobody running over the road is running a two speed rearend. most semis get 6 to 7 mpg. a 305/60/17 has a revs per mile of 642. 285/75r24. 5 revs per mile is 493. so they got the edge on a dodge their. all an 18 speed does is you split every gear in half to get a little extra help when pulling heavy. you have a 17-18% step up between gears with a 18 speed versus 36-38% step up with a 10 speed

 

[BDW]

You're absolutely right.



I think it has everything to do with the EPA making these trucks poop air out the tailpipe that is CLEANER than the air that goes into the intake.



Okay, maybe not that bad, but still. Emissions laws killed your fuel mileage. You can thank the EPA for that. God help those who use these trucks for business... almost makes more sense to buy a 12V, rebuild it and tune it for power. I get 18mpg with my '91 Ford V-8 diesel on the highway. VEE EIGHT!! 13 pulling a 10,000 pound horse trailer. There is no excuse for the newer trucks to not deliver better mileage than that, and my mileage was at 75-78 miles an hour. Not crawling at 60-65.

I drive an 06' 4X4 4DR HD and I promise i dont cut it any slack. I run 75-80 in the day light and 70-75 at night. I have a little over 6K on it now and have seen an increase in MPG in evey tank. Started out at just over 14MPG and my last fill up was 18. 2MPG. I pulled a 25' stock trailer half way across my home state and picked up a couple horses and came home. Lost less than 1MPG on the trip. Run 75-80 there and set the cruise at 70 for the trip home. with out a dout best truck (1st diesel) I have ever owned. If I didnt keep seeing the trailer in the rear view I wouldnt have known it was there!

 

[ROGER/DODGER]

I just turned over 13000 mi. on my 06, auto, Dually. After a long trip through the mountains pulling a 9000lb. RV the milage has gone up quite a bit don't know why, but I never ran more than 65 lb..... in the front tires, and now I run 80 lb. Hand calculated, 100 mi. at 2000 rpm 71 mph I got 19. 0 mpg It is slowly breaking in. I"m running Superchips, Amzoil air filter, cold air intake and a Aeroturbine 4040 muffler.

 

[dpuckett]

One thing I have not seen is that fuel usage vs weight isnt linear. I got 19mpg with a 7K truck (1stGen, but for this comparison, it will work), 18towing a 2200# tailer. Put on 8 tons of hay, and MPG only fell to 13-14. I tripled my weight or more, yet MPGs dropped only 33%. This was 3. 54 gears, 5spd, and driving 65-68mph. So there is only a certain amount MPGs will drop.



Plus, there are a lot of variables, esp with electronic controls. Plus, if you have an auto, lockup TC or not, I am not convinced that it is the same as a direct connect clutch. I think it is hard to gauge what the factors are in good vs bad MPGs, without gauges on everything from transmission line pressures, fuel pressure (both LP and rail), EGT, boost, backpressure, RPM, intake restirction, etc, etc. Plus, how did you break in your new engine? Did you work it now and then, or baby it the entire way? My experience tells me that trucks that work run better longer, often with better MPGs, than cream puffs.



Daniel

 

[J.BURCHFIELD]

This may be old information. Last time I drove a semi was 1982. With an empty flat bed you could get 7. 5 but loaded you got down to 5 to 5. 5. My 98 Ram 12v 2 wheel Q cab gets 17 and sometimes less on our interstate at 70 mph. That always gets mixed with some off the interstate driving. A diesel feels like it is happier when loaded. Was not designed to run around empty. Load a gas engine and the mileage really goes down dramatically. Seems like they formulate fuel differently when prices are up, it gives you less milage. Got no proof it just seems that way. Last semi tractor I owned was a Peterbuilt with a Catipillar engine. I turned up the fuel and got better milage because I was climbing the hills in higher gears. 1 to 1&1/2 mpg better. It was a cab-over and pushed a lot of air. Later models called Ant-eaters were streamlined to save fuel and it works. Was really glad to get back to a regular job. Being on the road every day got old in a hurry. It just ain't like Willie Nelson says in his song, "On the road again"

 

[MAshley]

A view some have missed in this thread....

There a few items that everyone has missed .....



HEAT. and the piston engine. No one in the last 50 years has delt with the heat issue of engines, heat is a wasted bi-product of ignighting a fuel, IE wasted energy that nets nothing for fuel economy, emmisions controlls use heat to produce a clean tail pipe but nothing for economy,



Pistion Engine. It moves, moving it takes energy, it creats its own heat and frition, Again nothing has changed sense day 1



What has happend the past 50 years



Hybrids 40ish MPG

Electric and gas engine, amazingly turning off the engine at a stop light saves gas and using a small engine + a electric motor to start going again and using braking power to recoop lost energy also makes the MPG go UP.

But still poor econmy if you ask me.

Would love to see a VW hybrid, small 2 or 3 cylinder diesel with a German designed electric system, should be really cool.



VW continues the diesel with excelent results.



Fuel cells, don't know much about them but, I don't ever remember hearing about a pistion in the equation. Oo.



Also some of the most efficiant ways of driving a car or truck are also some of the most boring and or time consuming ways, or non pratical. imagine a reactor in your car







One last comment, "assuming trailer use" A big semi and the CTD were designed to Haul heavy items, a common semi in the US is close to 80,000 LBS every day, and designed to be loaded at 80,000 every day. and gets 6-10 MPG depending on speed, terrain traveling accross, and driver habits.



A CTD every every day weighs in at 8,000 lbs and is designed to be at about 24,000 "again assuming trailer use" but I can only assume was designed to be at 24,000 every day. Other wise those of us who actually used the truck at 24,000 would destroy it in a matter of a few miles.

at max weight I acheve anywhere from 9 - 12 again depending on terrarin traveling accross, driver habits, and top speed.



So if we look at efficancy the Semi is better IE moves more material in a mile then I can with a CTD.



If we look at efficancy of moving my lazy *** "IE not walking that mile" the CTD is better, but than again the VW TDI is better still and then there is the hybrid if driven right, could do it all under electric power, so best economy of all



Ah but if we look at the efficancy of each semi and CTD the CTD wins



empty semi weighs in at about 40,000 lbs carrys about 40,000 for a max of 80,000 lbs 50% load at 6-10 MPG



a CTD weights in empty with a flat bed trailer at about 12,000 for a max of about 24,000 50% load at 9-12 MPG about a 50% gain in economy comparing 6 and 9 MPG